Exodus 13:11-16 - The Feast Of Unleavened Bread

¹¹ "Moreover, when the LORD hath brought thee into the land of the Canaanites, as he hath sworn unto thee and to thy fathers, and hath given it thee, ¹² then thou shalt appoint unto the LORD all that openeth the matrix, and all the firstborn among the beasts which thou hast if they be males. ¹³ And all the firstborn of the asses, thou shalt redeem with a sheep: if thou redeem him not, then break his neck. But all the firstborn among thy children shalt thou buy out.

¹⁴ And when thy son asketh thee in time to come, saying, 'What is this?' Thou shalt say unto him, 'With a mighty hand the LORD brought us out of Egypt, out of the house of bondage. ¹⁵ And when Pharaoh was loath to let us go, the LORD slew all the firstborn in the land of Egypt: as well the firstborn of men as of beasts. And therefore I sacrifice unto the LORD all the males that open the matrix, but all the firstborn of my children I must redeem.' ¹⁶ And this shall be as a token in thine hand, and as a thing hanged up between thine eyes: because the LORD brought us out of Egypt with a mighty hand."